Background: Combination of dexmedetomidine and opioid may be an alternative to high-dose opioid in attenuating cough during emergence from anesthesia, while also reducing the adverse effects of high-dose opioid. We tested the hypothesis that a single-dose of dexmedetomidine combined with low-dose remifentanil infusion during emergence would not be inferior to high-dose remifentanil infusion alone in attenuating cough after thyroidectomy. Methods: One hundred sixty-nine patients undergoing thyroidectomy were enrolled and randomized in a 1:1 ratio into group DR or group R. Each patient received an infusion of dexmedetomidine (0.5 μg/kg) and low-dose remifentanil infusion of effect-site concentration (Ce) at 1 ng/mL or normal saline and high-dose remifentanil infusion of Ce at 2 ng/mL for 10 min at the end of surgery. Remifentanil was maintained until tracheal extubation. Primary endpoint was the severity of coughing, which was assessed for non-inferiority using a four-point scale at the time of extubation. For comparison of coughing incidence during emergence, coughing grade was also measured at three times: before extubation, at extubation, and after extubation. Time to awakening, hemodynamic and respiratory profile, pain, and postoperative nausea and vomiting were also evaluated for superiority. Results: The 95% confidence intervals for differences in cough grade during tracheal extubation were <0.9, indicating non-inferiority of the single dose of dexmedetomidine combined with low-dose remifentanil infusion. The incidence of coughing was similar in the two groups. Hemodynamic changes during tracheal extubation were attenuated, but emergence from anesthesia was delayed, in group DR. Use of rescue antiemetic was similar in both groups, but the incidence of vomiting was less in group DR. Conclusion: A single-dose of dexmedetomidine (0.5 μg/kg) combined with low-dose remifentanil infusion at 1 ng/mL of Ce during emergence from sevoflurane-remifentanil anesthesia was not inferior to high-dose remifentanil infusion alone at 2 ng/mL of Ce with regard to suppressing cough.
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